JP2017227273A - Controller of power transmission for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that learning accuracy of a minimum pressure of a secondary sheave is deteriorated due to centrifugal force produced by rotation of an engine 12 during learning of an oil pressure sensor 110 in a vehicle in which the engine 12 and a primary sheave 66 of a continuously variable transmission 24 are unrotatably connected.SOLUTION: During learning of an oil pressure sensor 110 in the vicinity of a minimum oil pressure, an engine speed Ne is set to an idling speed Nei which is a low rotation speed, and thereby, rotation speed Npri of a primary sheave 66 is decreased, and fluctuation to an upshift of the primary sheave 66 which is generated on the basis of rotation of the primary sheave 66 can be decreased. Accordingly, learning accuracy of the secondary oil pressure sensor 110 in the vicinity of the minimum oil pressure can be improved.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a control device for a belt-type continuously variable transmission for a vehicle, and more particularly to learning control of hydraulic pressure of a belt-type continuously variable transmission for a vehicle.

  In the belt-type continuously variable transmission comprising a primary sheave and a secondary sheave each having a fixed sheave fixed to the rotating shaft and a movable sheave provided so as not to be relatively rotatable and movable in the direction of the rotating shaft. A vehicle is disclosed in which an input shaft to which engine output torque is always input during operation of the engine and a primary sheave of the belt type continuously variable transmission are connected. The vehicle of patent document 1 is it. By the way, in the vehicle using the belt type continuously variable transmission, the hydraulic pressure learning such as a hydraulic sensor for obtaining the hydraulic pressure supplied to the movable sheave of the belt type continuously variable transmission is performed before shipment from the vehicle factory or vehicle repair. It is generally performed while operating the engine before the subsequent delivery.

Japanese Patent No. 5444739

  In a vehicle in which the output torque of the engine is always input during engine operation in a vehicle in which the input shaft and the primary sheave are connected in Patent Document 1, a hydraulic pressure that measures the hydraulic pressure supplied to the movable sheave of the secondary sheave. The primary sheave is also rotated during sensor learning. For this reason, the hydraulic pressure supplied to the movable sheave of the primary sheave increases due to the centrifugal force generated by the rotation of the primary sheave. In particular, the hydraulic pressure supplied to the secondary sheave at the time of learning the minimum pressure of the secondary sheave, that is, the secondary sheave. During hydraulic pressure learning in a low state, the thrust ratio between the secondary sheave and the primary sheave (= the thrust of the secondary sheave / the thrust of the primary sheave) changes to a smaller side, that is, the upshift side. When the movement of the movable sheave of the primary sheave, that is, a shift occurs due to a change in the hydraulic pressure due to the centrifugal force based on the rotation of the primary sheave during the oil pressure learning, the oil pressure in the secondary sheave also changes and the oil pressure learning in the secondary sheave There is a risk that the accuracy of the lowering.

  The present invention has been made against the background of the above circumstances. The object of the present invention is to provide the belt-type continuously variable even in a vehicle in which the input shaft and the primary sheave are connected to rotate together. The purpose is to perform learning of the hydraulic sensor and the like for acquiring the hydraulic pressure supplied to the sheave of the transmission with high accuracy.

  The gist of the present invention is that: (a) a primary sheave connected to an input shaft to which the output torque of the engine is always inputted during operation of the engine, and a secondary around which a transmission belt is wound together with the primary sheave In a belt-type continuously variable transmission including a sheave, a control device for a vehicle power transmission device that performs learning of a hydraulic pressure sensor that acquires hydraulic pressure supplied to the secondary sheave, and (b) is supplied to the secondary sheave The engine rotational speed is controlled to a predetermined idle rotational speed when learning the sensor in the vicinity of the minimum hydraulic pressure to be performed.

  In this case, when learning the hydraulic sensor in the vicinity of the lowest hydraulic pressure supplied to the secondary sheave, the primary sheave is controlled by controlling the engine rotational speed to the low idle rotational speed. Suppresses the increase in hydraulic pressure based on the centrifugal force. As a result, it is possible to reduce the change to the upshift based on the rotation of the primary sheave, and the shift of the secondary sheave that is linked to the primary sheave is also suppressed. By suppressing the shift of the secondary sheave, the fluctuation of the hydraulic pressure in the secondary sheave is also suppressed, and the accuracy of learning of the hydraulic sensor near the minimum hydraulic pressure of the hydraulic pressure supplied to the secondary sheave is improved. The

It is a figure explaining the schematic structure of the vehicle to which the present invention is applied. It is a figure for demonstrating the switching of the running pattern of the power transmission device in the vehicle of FIG. It is a figure explaining the principal part of the control function and various control systems for various control in the vehicle of FIG. It is a figure explaining the part which controls the hydraulic pressure regarding a continuously variable transmission, a 1st clutch, a 2nd clutch, and a meshing type clutch among the hydraulic control circuits of FIG. FIG. 5 is a flowchart showing a control operation of an engine speed, a gear ratio, and a sheave pressure related to learning of the oil pressure of the secondary sheave in FIG. 4. 5 is an example of a time chart showing fluctuations in engine rotation speed, gear ratio, and sheave pressure related to learning of the hydraulic pressure of the secondary sheave in FIG. 4.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of a vehicle 10 to which the present invention is applied. In FIG. 1, a vehicle 10 includes an engine 12 such as a gasoline engine or a diesel engine that functions as a driving source for traveling, a driving wheel 14, and a power transmission device 16 provided between the engine 12 and the driving wheel 14. It has. The power transmission device 16 is connected to the torque converter 20 as a fluid transmission device connected to the engine 12, the input shaft 22 connected to the torque converter 20, and the input shaft 22 in a housing 18 as a non-rotating member. A belt type continuously variable transmission 24 (hereinafter referred to as a continuously variable transmission), a forward / reverse switching device 26 connected to the input shaft 22, and a continuously variable transmission connected to the input shaft 22 via the forward / reverse switching device 26. Gear transmission mechanism 28 as a gear transmission provided in parallel with the machine 24, the output shaft 30, which is a common output rotating member of the continuously variable transmission 24 and the gear transmission mechanism 28, the counter shaft 32, the output shaft 30, and the counter shaft A reduction gear device 34 composed of a pair of gears that are provided in mesh with each other and engaged with each other, and a differential 36 connected to a gear 36 provided with the counter shaft 32 so as not to be relatively rotatable. Ya 38 includes an axle 40 or the like of the pair coupled to a differential gear 38. In the power transmission device 16 configured as described above, the power of the engine 12 (the torque and the force are synonymous unless otherwise distinguished) is transmitted to the torque converter 20, the continuously variable transmission 24 or the forward / reverse switching device 26, and the gear transmission mechanism 28. The reduction gear device 34, the differential gear 38, the axle 40, and the like are sequentially transmitted to the pair of drive wheels 14.

  As described above, the power transmission device 16 transmits the power of the engine 12 to the engine 12 (here, the input shaft 22 which is an input rotating member to which the power of the engine 12 is transmitted) and the driving wheel 14 (here, the driving wheel 14 is transmitted). A gear transmission mechanism 28 serving as a first transmission unit and a continuously variable transmission 24 serving as a second transmission unit provided in parallel with a power transmission path between the output shaft 30 and an output rotating member that outputs the same. I have. Therefore, the power transmission device 16 transmits the power of the engine 12 from the input shaft 22 to the drive wheel 14 side (that is, the output shaft 30) via the gear transmission mechanism 28, and the power of the engine 12 is transmitted. A plurality of power transmission paths PT, which are the second power transmission path PT2 that is transmitted from the input shaft 22 to the drive wheel 14 side (that is, the output shaft 30) via the continuously variable transmission 24, are connected to the input shaft 22 and the output shaft 30. In parallel between. The power transmission device 16 is switched between the first power transmission path PT1 and the second power transmission path PT2 in accordance with the traveling state of the vehicle 10. Therefore, the power transmission device 16 has a plurality of engagements for selectively switching the power transmission path PT for transmitting the power of the engine 12 to the drive wheel 14 side between the first power transmission path PT1 and the second power transmission path PT2. Equipment. This engagement device is a first clutch as a first engagement device that connects and disconnects the first power transmission path PT1 (in other words, a first engagement device that is engaged to form the first power transmission path PT1). C1) and the first brake B1, and a second clutch C2 as a second engagement device for connecting and disconnecting the second power transmission path PT2.

  The torque converter 20 is provided coaxially with the input shaft 22 around the input shaft 22, and includes a pump impeller 20 p connected to the engine 12 and a turbine impeller 20 t connected to the input shaft 22. ing. The pump impeller 20p is supplied with hydraulic pressure for controlling the transmission of the continuously variable transmission 24, operating the plurality of engagement devices, and supplying lubricating oil to each part of the power transmission device 16. A mechanical oil pump 42 that is generated by being driven by rotation and supplied to the hydraulic control circuit 80 is connected. During operation of the engine 12, the output torque of the engine 12 is constantly input to the input shaft 22 via the torque converter 20.

  The forward / reverse switching device 26 is provided coaxially with the input shaft 22 around the input shaft 22 in the first power transmission path PT1, and includes a double pinion planetary gear device 26p, a first clutch C1, and a first clutch C1. One brake B1 is provided. The planetary gear device 26p is a differential mechanism having three rotating elements: a carrier 26c as an input element, a sun gear 26s as an output element, and a ring gear 26r as a reaction force element. The carrier 26c is integrally connected to the input shaft 22, the ring gear 26r is selectively connected to the housing 18 via the first brake B1, and the sun gear 26s is coaxial with the input shaft 22 around the input shaft 22. It is connected to a small-diameter gear 44 provided so as to be relatively rotatable. The carrier 26c and the sun gear 26s are selectively connected via the first clutch C1. Therefore, the first clutch C1 is an engagement device that selectively connects two of the three rotating elements, and the first brake B1 selectively connects the reaction element to the housing 18. It is an engaging device to do.

  The gear transmission mechanism 28 includes a small-diameter gear 44 and a large-diameter gear 48 that is provided around the gear mechanism counter shaft 46 so as not to rotate relative to the gear mechanism counter shaft 46 and meshes with the small-diameter gear 44. ing. The gear transmission mechanism 28 includes an idler gear 50 provided around the gear mechanism counter shaft 46 so as to be relatively rotatable coaxially with the gear mechanism counter shaft 46, and the output shaft 30 with respect to the output shaft 30. An output gear 52 that is provided on the coaxial center so as not to rotate relative to the idler gear 50 is provided. The output gear 52 has a larger diameter than the idler gear 50. Accordingly, the gear transmission mechanism 28 is a gear transmission mechanism in which one speed ratio (speed stage) as a predetermined speed ratio (speed stage) is formed in the power transmission path PT between the input shaft 22 and the output shaft 30. It is. Around the gear mechanism counter shaft 46, a meshing clutch D <b> 1 is provided between the large-diameter gear 48 and the idler gear 50 to selectively connect and disconnect between them. The meshing clutch D1 is provided in the power transmission device 16 and is disposed in a power transmission path between the forward / reverse switching device 26 (the first friction clutch also agrees) and the output shaft 30 (in other words, the above-described clutch). A third engagement device (provided on the output shaft 30 side of the first clutch C1) and the first power transmission path PT1 (in other words, the first power transmission by being engaged with the first clutch C1). The third engagement device that forms the path PT1) is included in the plurality of engagement devices.

  Specifically, the meshing clutch D1 includes a clutch hub 54 provided around the gear mechanism counter shaft 46 so as not to rotate relative to the gear mechanism counter shaft 46, an idler gear 50, and a clutch hub 54. A clutch gear 56 disposed between and fixed to the idler gear 50 is spline-fitted to the clutch hub 54 so that the gear mechanism counter shaft 46 cannot rotate relative to the shaft center and is parallel to the shaft center. And a cylindrical sleeve 58 provided so as to be relatively movable in various directions. The sleeve 58 that is always rotated integrally with the clutch hub 54 is moved to the clutch gear 56 side and meshed with the clutch gear 56, whereby the idler gear 50 and the gear mechanism counter shaft 46 are connected. Further, the meshing clutch D1 includes a known synchromesh mechanism S1 as a synchronizing mechanism that synchronizes rotation when the sleeve 58 and the clutch gear 56 are engaged. In the meshing clutch D1 configured as described above, the fork shaft 60 is operated by the hydraulic actuator 62, whereby the sleeve 58 is connected to the shaft of the gear mechanism counter shaft 46 via the shift fork 64 fixed to the fork shaft 60. It is slid in a direction parallel to the center, and the engaged state and the released state are switched.

  The first power transmission path PT1 is formed by engaging the meshing clutch D1 and the first clutch C1 (or the first brake B1) provided closer to the input shaft 22 than the meshing clutch D1. . A forward power transmission path is formed by the engagement of the first clutch C1, and a reverse power transmission path is formed by the engagement of the first brake B1. In the power transmission device 16, when the first power transmission path PT <b> 1 is formed, the power transmission state in which the power of the engine 12 can be transmitted from the input shaft 22 to the output shaft 30 via the gear transmission mechanism 28 is set. The On the other hand, the first power transmission path PT1 is in a neutral state (power transmission) that interrupts power transmission when at least the first clutch C1 and the first brake B1 are both released or at least the meshing clutch D1 is released. It is said that it is in a cut-off state.

  The continuously variable transmission 24 is provided on the input shaft 22 that rotates together with the engine 12 even when the engine 12 is in operation while the engine 12 is connected to the engine via the torque converter 20 and the second clutch C2 is released. A primary sheave (primary pulley) 66 having a variable effective diameter, a secondary sheave (secondary pulley) 70 having a variable effective diameter provided on a rotary shaft 68 coaxial with the output shaft 30, and the sheaves 66, 70. And a transmission belt 72 wound around the belt, and power is transmitted through frictional force (belt clamping pressure) between the sheaves 66, 70 and the transmission belt 72. In the primary sheave 66, the hydraulic pressure supplied to the primary sheave 66 (that is, the primary pressure Pin supplied to the primary hydraulic cylinder 66c) is driven by an electronic control device 90 (see FIGS. 3 and 4) corresponding to the control device. By controlling the pressure regulation by the circuit 80 (see FIGS. 3 and 4), a primary thrust Win (= primary pressure Pin × pressure receiving area) for changing the V groove width between the fixed sheave 66a and the movable sheave 66b is applied. In the secondary sheave 70, the hydraulic pressure supplied to the secondary sheave 70 (that is, the secondary pressure Pout supplied to the secondary hydraulic cylinder 70c) is regulated by the hydraulic control circuit 80, so that the fixed sheave 70a and the movable sheave 70b are controlled. A secondary thrust Wout (= secondary pressure Pout × pressure receiving area) is applied to change the V groove width therebetween. In the continuously variable transmission 24, the primary thrust Win (primary pressure Pin) and the secondary thrust Wout (secondary pressure Pout) are controlled, so that the V-groove widths of the sheaves 66 and 70 change and the transmission belt 72 is engaged. The diameter (effective diameter) is changed, the gear ratio γcvt (= primary sheave rotation speed Npri / secondary sheave rotation speed Nsec) is changed, and the sheaves 66 and 70 and the transmission belt are prevented from slipping. The frictional force with 72 is controlled.

  The output shaft 30 is disposed around the rotation shaft 68 so as to be rotatable relative to the rotation shaft 68 coaxially. The second clutch C2 is provided on the drive wheel 14 (here, the output shaft 30 also agrees) side with respect to the continuously variable transmission 24 (that is, provided between the secondary sheave 70 and the output shaft 30). The secondary sheave 70 (rotary shaft 68) and the output shaft 30 are selectively connected or disconnected. The second power transmission path PT2 is formed by engaging the second clutch C2. In the power transmission device 16, when the second power transmission path PT <b> 2 is formed, a power transmission possible state in which the power of the engine 12 can be transmitted from the input shaft 22 to the output shaft 30 via the continuously variable transmission 24. Is done. On the other hand, the second power transmission path PT2 is set to the neutral state when the second clutch C2 is released.

  The operation of the power transmission device 16 will be described below. FIG. 2 is a diagram for explaining the switching of the travel pattern using the engagement table of the engagement device for each travel pattern (travel mode) of the power transmission device 16 switched by the electronic control device 90. In FIG. 2, C1 corresponds to the operating state of the first clutch C1, C2 corresponds to the operating state of the second clutch C2, B1 corresponds to the operating state of the first brake B1, and D1 corresponds to the meshing clutch D1. Corresponding to the operating state, “◯” indicates engagement (connection), and “×” indicates release (cutoff).

  FIG. 3 is a diagram for explaining the main functions of the control function and the control system for various controls in the vehicle 10. In FIG. 3, the vehicle 10 includes an electronic control device 90 including a control device for the power transmission device 16, for example. Therefore, FIG. 3 is a diagram showing an input / output system of the electronic control unit 90, and is a functional block diagram for explaining a main part of a control function by the electronic control unit 90. The electronic control unit 90 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM and follows a program stored in the ROM in advance. Various controls of the vehicle 10 are executed by performing signal processing. For example, the electronic control unit 90 executes output control of the engine 12, shift control of the continuously variable transmission 24, travel pattern switching control of the power transmission device 16, and the like. The electronic control unit 90 is configured separately for engine control, hydraulic control, and the like as necessary.

  The electronic control unit 90 includes various actual values based on detection signals from various sensors provided in the vehicle 10, such as various rotational speed sensors 100, 102, 104, 106, an accelerator opening sensor 108, a secondary sheave hydraulic sensor 110, and the like, for example, an engine. Output shaft corresponding to the rotational speed Ne (rpm), the primary sheave rotational speed Npri (rpm) as the input shaft rotational speed Nin (rpm), the secondary sheave rotational speed Nsec (rpm) as the rotational speed of the rotational shaft 68, and the vehicle speed V A rotation speed Nout (rpm), an accelerator opening degree θacc (%), a secondary pressure Pout (MPa), and the like are supplied. The electronic control unit 90 also outputs an engine output control command signal Se for output control of the engine 12, a hydraulic control command signal Sccv for hydraulic control related to the shift of the continuously variable transmission 24, and a travel pattern of the power transmission device 16. The hydraulic control command signal Sswt and the like for controlling the first clutch C1, the first brake B1, the second clutch C2, and the meshing clutch D1 are output. For example, as a hydraulic control command signal Sswt, for driving each solenoid valve that regulates each hydraulic pressure supplied to each hydraulic actuator of the first clutch C1, the first brake B1, the second clutch C2, and the meshing clutch D1. A command signal (hydraulic command) is output to the hydraulic control circuit 80.

  FIG. 4 illustrates a portion of the hydraulic control circuit 80 provided in the power transmission device 16 that controls the hydraulic pressure related to the continuously variable transmission 24, the first clutch C1, the second clutch C2, and the meshing clutch D1. FIG. The hydraulic control circuit 80 controls the primary solenoid valve SLP that controls the primary pressure Pin supplied to the primary sheave 66, the secondary solenoid valve SLS that controls the secondary pressure Pout supplied to the secondary sheave 70, and the first clutch C1. The C1 solenoid valve SL1 for controlling the supplied C1 pressure Pc1, the C2 solenoid valve SL2 for controlling the C2 pressure Pc2 supplied to the second clutch C2, and the synchro control supplied to the hydraulic actuator 62 for operating the synchromesh mechanism S1. And a synchro solenoid valve SLG for controlling the pressure Ps1. The hydraulic control circuit 80 includes a primary pressure control valve 82, a secondary pressure control valve 84, a C1 pressure control valve 86, and a synchro control valve 88. Further, a hydraulic sensor 110 for detecting the hydraulic pressure of the secondary sheave 70 is further provided between the orifice 85 and the secondary sheave 70 in the oil passage connecting the hydraulic control circuit 80 and the secondary sheave 70.

  Each of the solenoid valves SLP, SLS, SL1, SL2, and SLG is a linear solenoid valve that is driven by a hydraulic control command signal (drive current) output from the electronic control unit 90. The primary pressure control valve 82 is operated based on the SLP pressure Pslp output from the primary solenoid valve SLP to regulate the primary pressure Pin. The secondary pressure control valve 84 regulates the secondary pressure Pout by being operated based on the SLS pressure Psls output from the secondary solenoid valve SLS. The synchro control valve 88 is operated based on the SLG pressure Pslg output from the synchro solenoid valve SLG to regulate the synchro control pressure Ps1. The C1 pressure control valve 86 switches between connection and disconnection of the oil passage that supplies the SL1 pressure Psl1 output from the C1 electromagnetic valve SL1 as the C1 pressure Pc1 to the first clutch C1. The C1 pressure control valve 86 avoids simultaneous engagement of the first clutch C1 and the second clutch C2 by shutting off an oil passage that supplies the C1 pressure Pc1 (SL1 pressure Psl1 is also agreed) to the first clutch C1. Functions as a fail-safe valve. The SL2 pressure Psl2 output from the C2 solenoid valve SL2 is directly supplied to the second clutch C2 as the C2 pressure Pc2.

  In a vehicle including the continuously variable transmission 24, the detected value of the hydraulic sensor 110 that detects the secondary pressure Pout supplied to the movable sheave 70b of the secondary sheave 70 of the continuously variable transmission 24 and the indicated pressure of the secondary pressure Pout, that is, the secondary pressure. Learning of the relationship between the secondary pressure control signal (indicated pressure) to the control valve 84 is performed before shipment from the vehicle factory, before delivery after vehicle repair, or the like. In FIG. 3, the main part of the control function relating to learning of the hydraulic sensor 110 that measures the secondary pressure Pout supplied to the movable sheave 70b, that is, the gear ratio determining means 94, the hydraulic sensor learned value determining means 96, the hydraulic sensor learned value. Learning control means 92 including storage means 98 is shown. When the electronic control unit 90 receives a flag signal requesting the start of learning control of the hydraulic sensor 110, the learning control unit 92 starts learning including minimum pressure learning and intermediate pressure learning of the hydraulic sensor 110. The minimum pressure learning corresponds to the lowest hydraulic pressure within the control range of the secondary pressure Pout in which the hydraulic pressure supplied to the movable sheave 70b of the secondary sheave 70 is low, that is, the maximum transmission ratio γmax at which the transmission ratio γcvt is the maximum value can be maintained. This is learning between the detected value of the hydraulic sensor 110 and the secondary pressure control signal (indicated pressure) to the secondary pressure control valve 84. The learning control unit 92 sets the oil pressure of the primary sheave 68 to a predetermined low oil pressure P1 through the oil pressure control circuit 80 so that the transmission belt 72 and the primary sheave 66 maintain an appropriate frictional force. The learning control means 92 maintains the engine rotational speed Ne at an idle rotational speed Nei of, for example, about 800 rpm in the minimum pressure learning period, and a medium speed of, for example, about 2000 rpm in order to ensure an oil amount balance in the subsequent intermediate pressure learning period. So that the engine output command signal Se is output. Further, the learning control unit 92 temporarily increases the command pressure of the secondary pressure Pout to the secondary sheave 70, and then decreases the command pressure to a preset command pressure at the time of learning the minimum pressure. When a change in the transmission gear ratio γcvt (decrease from the maximum transmission gear ratio γmax) is determined by the transmission gear ratio determining means 94, the detected value of the hydraulic pressure sensor 110 is determined to be the lowest hydraulic pressure that can maintain the maximum transmission gear ratio γmax of the transmission gear ratio γcvt. To do. The hydraulic sensor learned value storage unit 98 stores the detected value of the hydraulic sensor 110 at the lowest hydraulic pressure at which the maximum speed ratio γmax determined by the hydraulic sensor learned value determination unit 96 can be maintained together with the command pressure.

  The learning control unit 92 increases the engine speed Ne to the medium speed rotation in the gear ratio return period preceding the intermediate pressure learning period following the minimum pressure learning period, thereby increasing the secondary pressure Pout. While ensuring the balance, the gear ratio γcvt is returned to the maximum gear ratio γmax by increasing the command pressure of the secondary pressure Pout to the first pressure P4. Next, after the gear ratio γcvt and the engine speed Ne are stabilized in the gear ratio return period, the learning control unit 92 changes the command pressure of the secondary pressure Pout from the first pressure P4 to the second pressure in the next intermediate pressure learning period. The pressure P5 and the third pressure P6 are sequentially increased, the detected value of the hydraulic sensor 110 and the command pressure at that time are stored, and the relationship between the detected value of the hydraulic sensor 110 and the command pressure is learned. Further, the learning control means 92 stores the detected value and the indicated value of the hydraulic pressure sensor 110 when the indicated pressure of the secondary pressure Pout is reduced to the first pressure P4 in the hysteresis check period following the intermediate pressure learning period. The hysteresis characteristic of the sensor 110 is learned.

  FIG. 5 shows the main part of the control operation of the electronic control unit 90, that is, the learning of the minimum hydraulic pressure of the hydraulic sensor 110 that detects the hydraulic pressure supplied to the secondary sheave 70 in the minimum pressure learning period, and the influence of the engine speed Ne is reduced. This is a flowchart for explaining the control operation for improving the learning accuracy, and is repeatedly executed at various necessary timings such as before shipment from the vehicle factory and before delivery after vehicle repair.

  In FIG. 5, it is determined whether or not a flag signal requesting the start of learning control has been received in step S <b> 10 (hereinafter, step is omitted) corresponding to the function of the learning control unit 92. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is affirmative, in S20 corresponding to the function of the learning control means 92, the primary pressure Pin is set to a predetermined hydraulic pressure P1 to be used in the minimum pressure learning control. Further, in S30 corresponding to the function of the learning control means 92, the engine speed Ne is set to the idle speed Nei. Further, in S40 corresponding to the function of the learning control means 92, the command pressure of the secondary pressure Pout is temporarily increased and then set to the command oil pressure at the time of learning the preset minimum pressure. In S50 corresponding to the functions of the speed ratio determining means 94 and the hydraulic sensor learned value determining means 96, a change in the speed ratio γcvt (decrease in the maximum speed ratio γmax) is determined, and the oil pressure when the change is determined is changed to the maximum speed. The output of the hydraulic sensor 110 is learned as the minimum hydraulic pressure that can maintain the ratio γmax. Further, in S60 corresponding to the function of the hydraulic sensor learning storage means 98, the learning value is stored.

  FIG. 6 is a time chart showing changes in the engine speed Ne, the gear ratio γcvt, the secondary pressure Pout, and the primary pressure Pin related to learning of the secondary pressure Pout in the learning control. When the learning control flag of the hydraulic sensor 110 is set at time t1, that is, when a flag signal requesting the start of learning control is received, a series of learning including predetermined minimum pressure learning and intermediate pressure learning is started. . First, the primary pressure Pin of the primary sheave 66 is set to a predetermined oil pressure P1, and the engine rotation speed Ne is set to the idle rotation speed Ne. Thereafter, the command pressure of the secondary pressure Pout is temporarily increased from P2 to P7 at the time t1, and the transmission gear ratio γcvt is surely set to the maximum transmission gear ratio γmax, and then decreased toward P3. In the minimum pressure learning period from the time t2 to the time t3, the engine rotational speed Ne is maintained at the idle rotational speed Nei, and the command pressure of the secondary pressure Pout is maintained at the pressure P3 necessary for the minimum pressure learning. Accordingly, the minimum pressure of the secondary pressure Pout is determined based on the reduction of the transmission ratio γcvt from γ4, that is, the maximum transmission ratio γmax to γ3, and the detected value of the secondary sheep hydraulic pressure sensor 110 at the minimum pressure is the secondary pressure Pout. It is stored together with the indicated value.

  After t3, a time chart from the completion of the minimum pressure learning to the completion of writing after the control called the intermediate pressure learning and the hysteresis check is performed is shown. Other than the minimum pressure learning, since it is not directly related to the present invention, a detailed description of the contents of the gear ratio return period and the intermediate pressure learning period after time t3 is omitted. At time t3, the engine rotational speed Ne is increased from the idle rotational speed Nei to Ne2, and the amount of oil supplied from the oil pump 42 is increased to an amount of oil that is not insufficient in learning after the time t4. Further, the command pressure of the secondary pressure Pout is increased to the first pressure P4, and the gear ratio γcvt is set to γ4, that is, the maximum gear ratio γmax. When the engine speed Ne reaches Ne2 at time t4, learning of the intermediate pressure, that is, the first pressure P4, the second pressure P5, and the third pressure P6 from the time t4 to the time t7 is started. After the time t4, the gear ratio γcvt is maintained at γ4, that is, the maximum gear ratio γmax when the learning control flag is set. The command pressure of the secondary pressure Pout is set to the second pressure P5 at time t5 and the third pressure P6 at time t6. Further, from the time t7 to the time t8, the command pressure of the secondary pressure Pout is temporarily reduced to the first pressure P4 and the hysteresis check is performed. Then, the data learned from the time t8 is stored, and the learning is completed at the time t9. .

  Here, the engine transfer rate Ne indicated by a broken line from the time point t1 to the time point t4 in FIG. 6 indicates a generally performed method unlike the present embodiment. At the engine speed Ne indicated by a broken line, the engine speed Ne is increased from time t1 toward Ne2 in order to ensure the necessary oil pressure during a series of learning from the oil pump 42 until learning is completed, that is, time t9. The rotational speed Ne of the engine 12 is maintained at Ne2. However, in the vehicle 10 in which the input shaft 22 to which the power of the engine 12 is transmitted and the primary sheave of the continuously variable transmission 24 are non-rotatably coupled, the primary sheave 66 is rotated by the engine 12 even during learning control. ing. In particular, at the time of the lowest pressure learning, that is, from the time t2 to the time t3, the hydraulic pressure of the secondary sheave 70 is reduced to P3 for the lowest pressure learning. At this time, the thrust ratio between the secondary sheave 70 and the primary sheave 66 (= the thrust of the secondary sheave / the thrust of the primary sheave) is likely to cause an upshift as the thrust of the secondary sheave 70 is reduced. . Further, when the engine speed Ne is high and the speed ratio γcvt is on the maximum speed ratio γmax side, the difference between the rotational speed Nsec of the secondary sheave 70 and the rotational speed Npri of the primary sheave 66 becomes larger. The centrifugal force generated in the primary sheave 66 is also larger on the primary sheave 66 side. Due to the centrifugal hydraulic pressure generated by the centrifugal force, the thrust of the primary sheave 66 is increased, and an upshift is more likely to occur. When the upshift occurs, movement of the movable sheaves 66b and 70b, that is, shift occurs, and the movement of the movable sheaves 66b and 70b increases the difference between the output hydraulic pressure in the hydraulic control circuit 80 and the hydraulic pressures Pin and Pout in the movable sheaves 66b and 70b. A so-called override pressure is generated. The override pressure is generated by the resistance of the orifice and oil passage between the hydraulic control circuit 80 and the movable sheaves 66b and 70b, and increases as the moving speed of the movable sheaves 66b and 70b increases. In addition, the occurrence of the override pressure causes a change in the hydraulic pressure in the movable sheave and a difference from the command hydraulic pressure, so that an error in learning of the secondary hydraulic pressure sensor 110 occurs particularly in the minimum pressure learning.

  According to the solid line at the engine speed Ne from t1 to t3 shown in FIG. 6, that is, according to the present invention, the engine speed Ne is set to the idle speed Nei, which is a low speed, as compared with the above. The rotational speeds Nsec and Npri of the primary sheave 66 and the primary sheave 66 are reduced. As a result, the centrifugal force generated in the secondary sheave 70 and the primary sheave 66 is reduced, and an upshift is less likely to occur. Even if an upshift occurs, if the engine speed Ne is decreased, the change of the gear ratio γcvt, that is, the shift that is the movement of the secondary sheave 70 and the primary sheave 66 is decreased, so that the learning of the secondary hydraulic sensor 110 is performed. The override pressure causing the error is also reduced, and the learning accuracy can be increased.

  According to the present embodiment, in a vehicle in which the engine 12 and the primary sheave 66 are non-rotatably connected via the input shaft 22, the hydraulic sensor 110 before shipping from the vehicle factory, before delivery after vehicle repair, or the like. When learning is performed in the vicinity of the minimum hydraulic pressure of the hydraulic pressure supplied to the secondary sheave 70, the primary sheave 66 is also rotated by the rotation of the engine 12, and is supplied to the movable sheave 66b of the primary sheave 66 by the centrifugal force generated by the primary sheave 66. In particular, when the minimum pressure of the secondary sheave 70 is learned, that is, when the hydraulic pressure supplied to the secondary sheave 70 is low, the learning accuracy of the minimum pressure of the secondary sheave 70 can be suppressed from decreasing. According to the present embodiment, even when the engine 12 and the primary sheave 66 are non-rotatably connected via the input shaft 22, the engine rotational speed Ne is set during learning of the hydraulic sensor 110 near the minimum hydraulic pressure. By setting the idle rotational speed Nei, which is a low rotational speed, the rotational speed Npri of the primary sheave 66 can be reduced, and fluctuations to the upshift side of the primary sheave 66 caused by the rotation of the primary sheave 66 are reduced. It becomes possible to decrease. Thereby, the shift of the secondary sheave 70 that shifts in conjunction with the primary sheave 66 is also suppressed. By suppressing the shift of the secondary sheave 70, the fluctuation of the secondary pressure Pout is also suppressed, and the learning accuracy of the secondary hydraulic sensor 110 near the minimum hydraulic pressure is improved.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  In the above-described embodiment, the power of the engine 12 is connected from the input shaft 22 to the input shaft 22 to the drive wheel 14 side via the gear transmission mechanism 28 as a gear transmission portion provided in parallel with the continuously variable transmission 24. There are a plurality of power transmission paths PT1 including a first power transmission path PT1 for transmission and a second power transmission path PT2 for transmitting the power of the engine 12 from the input shaft 22 to the drive wheel 14 via the continuously variable transmission 24. However, the present invention is not limited to this mode. For example, only the second power transmission path PT2 that transmits power via the continuously variable transmission 24 may be provided.

  In the embodiment, the engine rotational speed Ne at the time of learning the minimum pressure is set to the idle rotational speed Nei, that is, the engine rotational speed Ne set to maintain the engine 12 at the low rotational speed Ne. It is not necessary to be Nei, and any engine rotational speed Ne that can ensure sufficient accuracy as a learned value of the hydraulic pressure sensor 110 in the minimum pressure learning may be used.

  Furthermore, in the above-described embodiment, the engine 12 is exemplified as the driving force source, but the present invention is not limited to this. For example, the driving force source may employ another prime mover such as an electric motor alone or in combination with the engine 12. Further, the power of the engine 12 is transmitted to the input shaft 22 via the torque converter 20, but the present invention is not limited to this. For example, instead of the torque converter 20, another fluid transmission device such as a fluid coupling (fluid coupling) having no torque amplification action may be used. Alternatively, this fluid transmission device is not necessarily provided.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

12: engine 16: vehicle power transmission device 22: input shaft 24: continuously variable transmission (belt type continuously variable transmission)
66: Primary sheave 70: Secondary sheave 90: Electronic control device (control device)
110: Secondary sheave hydraulic sensor, hydraulic sensor (sensor)
Ne: Engine speed Nei: Idle speed

Claims (1)

In a belt-type continuously variable transmission comprising: a primary sheave connected to an input shaft to which the engine output torque is always input during operation of the engine; and a secondary sheave around which a transmission belt is wound together with the primary sheave. A control device for a vehicle power transmission device that performs learning of a hydraulic pressure sensor that acquires hydraulic pressure supplied to the secondary sheave,
A control device for a vehicle power transmission device, wherein the engine rotational speed is controlled to a predetermined idle rotational speed when learning the sensor in the vicinity of a minimum hydraulic pressure of the hydraulic pressure supplied to the secondary sheave. .

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